Marong map unit Dgf

Back to: A Land Capability Study of the Rural City of Marong

Map Unit:	Devonian granodiorite, very gentle slope	Map Unit Symbol:	Dgf
		% of Study Area:	0.6

Land-form diagram for Marong map unit Dgf

General Description:
Very gentle slopes are uncommon in this granitic land system. They occur in the lower positions of the landscape. Like the gentle crests and slopes the soils are yellow duplex with hardsetting bleached horizons and mottled heavy clay subsoils. Minor drainage lines have been included within this unit when they are too small to map individually. They often have similar soil types but are slightly wetter and may have uniform sandy soils. Outcropping tors occur occasionally and at random.

Site characteristics:

Parent material age:	Devonian	Depth seasonal watertable:	> 2 m
Lithology:	Granodiorite	Potential recharge to groundwater:	Low
Landform Pattern:	Undulating low hills	Flooding risk:	Nil
Element:	Slope	Drainage:	Moderately well drained
Slope common:	2%	Depth to hardrock:	1.2 m
Slope range:	1 - 3%
Rock outcrop:	< 2%

Major vegetation: Grey Box, Long-leaf Box, Red Gum, Yellow Box, Yellow Gum, Lightwood, Melaleuca spp. Rye Grass, Wallaby Grass, Onion Grass

Present land use: Sheep grazing (major)

Land degradation:	Water erosion		Wind erosion	Salting	Acidification
Land degradation:	Sheet/rill	Gully	Wind erosion	Salting	Acidification
Susceptibility	Low	High	High	Low	Low
Incidence	Low	Moderate	Low	Low	Low

Soil profile characteristics:

Permeability (measured - average, range):	7, 3 - 12 mm/day
Permeability (estimated):
Available water capacity:	210 mm H₂O
Linear shrinkage (B horizon):	14.2 %

Soil profile description:

A1	0-9 cm	Greyish yellow brown (10YR4/2) sandy loam, weak structure, angular blocky peds 10-20 mm, rough fabric, very weak consistence, pH 5.0 Clear transition to
A21	9-23 cm	Dull yellow orange (10YR6/3) sandy loam, bleached (7.5YR8/4) when dry, weak structure, subangular blocky peds 10-20 mm, rough fabric, very weak consistence, pH 5.3. Clear transition to
A22	23-38 cm	Dull yellow orange (10YR7/3) sandy loam, bleached when dry, apedal, sandy fabric, loose consistence, common granitic fragments, pH 5.7. Clear transition to
B23	8-76 cm	Greyish yellow brown (10YR6/2) heavy clay, many distinct medium sized red mottles, weak structure, subangular blocky peds 20-50 mm, smooth fabric, very firm consistence, pH 5.6. Clear transition to
B3	76-120 cm	Greyish brown (7.5YR5/2) light day, many faint coarse red mottles, moderate structure, angular blocky peds 10-20 mm, smooth fabric, moderately firm consistence, many coarse granitic fragments; pH 5.1.
C	120 cm	Hardpan

Soil classification:

Factual Key (Northcote):	Dy 3.41
Australian Soil Classification:	Bleached-Sodic, Mesotrophic, Grey, Chromosol; deep, thick, loamy, non-gravelly
Unified Soil Group:	CH

Interpretation of soil analyses*

Horizon	pH	Gravel %	E.C. (salts)	Nutrient Status	P	K	Al	Organic Matter	Dispersibility
A1	5.0**	3.1	VL	VL	U	S	S	H	L
A21	5.3**	7.3	M	VL	D	D	S	L	L
A22	5.7	15.1	H	D	D	D	S	L	L
B23	5.6	6.3	H	M	D	S	S	VL	H
B3	5.1**	14.4	H	M	D	S	S	VL	H

VL : Very Low; L : Low; M : Moderate; H : High; VH : Very High; D : Deficient; S : Satisfactory; T : Toxic; **: Acid * See Appendix 4 for analytical results

Land capability assessment

Land Use	Class	Major limiting feature(s)/ landuse
Agriculture (CTS values)	C₃T₂S₄	Highly susceptible to wind and gully erosion, high electrical conductivity in subsoil
Effluent disposal (septic tanks)	5	Very slow permeability
Farm dams (earthen)	4	Shallow depth to hardpan, highly dispersible subsoil, low suitability of subsoil
Building foundations - slab	3	Moderate drainage
Building foundations - stumps/footings	3	Moderate drainage, moderate linear shrinkage
Secondary roads	3	Moderate drainage, moderate linear shrinkage, Universal Soil Group
Urban residential	3	Secondary roads, building foundations
Rural residential	5	Effluent disposal

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